to forcebaly smack someone on the forehead with a penis, thuse leaving a mushroom-shaped wealt on face
dude i so mushroom tapped that chick
by faroramzes October 29, 2003
the act of tapping the head of your penis on a girls head during oral sex.
Lat night, when I was getting head, I mushroom tapped that chick.
by dom s November 17, 2007